![]() In MySQL, you can store UUID values in a compact format ( BINARY) and display them in human-readable format ( VARCHAR) with help of the following functions: Using UUID values may cause performance issues due to their size and not being ordered.Debugging seems to be more difficult, imagine the expression WHERE id = 'df3b7cb7-6a95-11e7-8846-b05adad3f0ae' instead of WHERE id = 10.Storing UUID values (16-bytes) takes more storage than integers (4-bytes) or even big integers(8-bytes).By using UUID, you can generate the primary key value of the parent table up front and insert rows into both parent and child tables at the same time within a transaction.īesides the advantages, UUID values also come with some disadvantages: For example, to insert data into a parent table and child tables, you have to insert into the parent table first, get generated id and then insert data into the child tables. ![]() It also simplifies logic in the application. UUID values can be generated anywhere that avoid a round trip to the database server.For example, if a customer with id 10 accesses his account via URL, it is easy to guess that there is a customer 11, 12, etc., and this could be a target for an attack. UUID values do not expose the information about your data so they are safer to use in a URL.UUID values are unique across tables, databases, and even servers that allow you to merge rows from different databases or distribute databases across servers.Using UUID for a primary key brings the following advantages: + -+Ĭode language: SQL (Structured Query Language) ( sql ) MySQL UUID vs. The UUID() function returns a UUID value in compliance with UUID version 1 described in the RFC 4122.įor example, the following statement uses the UUID() function to generate a UUID value: mysql> SELECT UUID() To generate UUID values, you use the UUID() function as follows: UUID() In MySQL, a UUID value is a 128-bit number represented as a utf8 string of five hexadecimal numbers in the following format: aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeeeĬode language: SQL (Structured Query Language) ( sql ) Two UUID values are expected to be distinct, even they are generated on two independent servers. UUID is designed as a number that is unique globally in space and time. UUID is defined based on RFC 4122, “a Universally Unique Identifier (UUID) URN Namespace). UUID stands for Universally Unique IDentifier. The code for ReplicationType: defmodule doĪlias : this tutorial introduces you to MySQL UUID, shows you to use it as the primary key (PK) for a table, and discusses the pros and cons of using it as the primary key. SELECT r0.`id`, r0.`name`, r0.`inserted_at`, r0.`updated_at` FROM `replication_types` AS r0 WHERE (r0.`name` = ?) Iex(6)> Repo.get_by(ReplicationType, name: "test3")ġ8:33:11.506 QUERY OK source="replication_types" db=8.9ms ![]() I believe I’m doing something dumb but, at least for me, the dumber it is the harder it is to find. Code for the schema and repo follow the example. When I query the record, I get a different UUID back. A record is created, and the UUID is shown. When I create a record, I generate the UUID for the id, and pass that along with the other fields to insert. I’m having a vexing issue using Ecto.UUIDs as my primary key in a table.
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